kFileSystemTypeIsolated should be only used in the URL exposed to renderer

webkit/fileapi/file_system_url.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "webkit/fileapi/file_system_url.h"
 
 #include "webkit/fileapi/file_system_types.h"
 #include "webkit/fileapi/file_system_util.h"
 #include "webkit/fileapi/isolated_context.h"
 
 namespace fileapi {
 
 FileSystemURL::FileSystemURL()
     : type_(kFileSystemTypeUnknown),
-      mount_type_(kFileSystemMountTypeUnknown),
       is_valid_(false) {}
 
 FileSystemURL::FileSystemURL(const GURL& url)
-    : type_(kFileSystemTypeUnknown),
-      mount_type_(kFileSystemMountTypeUnknown) {
+    : type_(kFileSystemTypeUnknown) {
   is_valid_ = CrackFileSystemURL(url, &origin_, &type_, &virtual_path_);
   MayCrackIsolatedPath();
 }
 
 FileSystemURL::FileSystemURL(
     const GURL& origin,
     FileSystemType type,
     const FilePath& path)
     : origin_(origin),
       type_(type),
@@ skipping 19 matching lines @@
   return origin_ == that.origin_ &&
       type_ == that.type_ &&
       path_ == that.path_ &&
       virtual_path_ == that.virtual_path_ &&
       filesystem_id_ == that.filesystem_id_ &&
       is_valid_ == that.is_valid_;
 }
 
 void FileSystemURL::MayCrackIsolatedPath() {
   path_ = virtual_path_;
+  mount_type_ = type_;
   if (is_valid_ && IsolatedContext::IsIsolatedType(type_)) {
-    mount_type_ = static_cast<FileSystemMountType>(type_);
     // If the type is isolated, crack the path further to get the 'real'
     // filesystem type and path.
     is_valid_ = IsolatedContext::GetInstance()->CrackIsolatedPath(
         virtual_path_, &filesystem_id_, &type_, &path_);
   }
 }
 
 }  // namespace fileapi